Bicalutamide for advanced prostate cancer: the natural versus treated history of disease.

PURPOSE: To determine the therapeutic effects of bicalutamide 200 mg in patients with prostate cancers of different hormone sensitivities. METHODS: Patients with progressive prostate cancer were treated with bicalutamide 200 mg daily. Before treatment, patients' tumors were classified on the basis of prior hormone exposure and by serum testosterone levels into androgen-dependent and androgen-independent groups. Prior exposure to flutamide and response to flutamide withdrawal was also considered. Outcomes were reported independently on the basis of posttherapy changes in prostate-specific antigen (PSA), measurable disease, and radionuclide bone scans. RESULTS: Outcomes varied by prior hormone exposure as a higher proportion of patients with progression of androgen-dependent tumors showed posttherapy PSA decreases of more than 50% or more than 80%, measurable disease regression, and improvement on radionuclide bone scans than did patients with androgen-independent progression. Within the category of androgen-independent progression, clinical benefit was observed in patients who had previously progressed on flutamide, independent of the response to flutamide withdrawal. Patients who had progressed on a gonadotropin-releasing hormone (GnRH) analog alone had a low response proportion, whereas those who progressed after two or more hormone therapies did not respond. Overall, the drug was well tolerated. After progression on bicalutamide monotherapy, one third of patients with androgen-dependent progression responded to medical castration with a GnRH analog. CONCLUSION: Classifying patient tumors on the basis of prior hormone exposure permits a more precise estimate of the potential benefit of a specific hormone therapy for the individual patient. The precision is further increased by reporting the effects of a drug on each parameter of disease independently. The difference in outcomes for patients with androgen-independent progression suggests that the specific hormone therapy administered and the response to that therapy can influence the biology of the relapsing tumor and the sensitivity to subsequent therapies. The sensitivity to bicalutamide after progression on flutamide deserves further study.

Post-therapy change in prostate-specific antigen levels as a clinical trial endpoint in hormone-refractory prostatic cancer: a trial with 10-ethyl-deaza-aminopterin.

OBJECTIVES: Serial changes in prostate-specific antigen (PSA) correlate with disease status in all stages of prostatic cancer. For hormone-refractory disease, post-therapy declines of 50% and 80% from baseline are associated with an improved survival. This study sought to evaluate edatrexate, a synthetic antifolate, in hormone-refractory prostatic cancer using post-therapy PSA change as the initial endpoint. METHODS: Fourteen patients with progression of disease despite castrate levels of testosterone received edatrexate. Serial changes in PSA were monitored and correlated with other parameters of outcome. RESULTS: Stabilization of a rising PSA level in parallel with clinical stabilization of disease was observed in one patient; disease in all others progressed. Toxic reactions were acceptable. CONCLUSIONS: With no objective evidence for antitumor activity as assessed by post-therapy PSA changes in any of the patients treated, edatrexate seems a poor candidate for future study. The use of post-therapy PSA change as the initial screening modality allows treatments to be evaluated rapidly in patients without measurable disease. The methodology proposed will require validation in prospective phase III investigations using survival as the endpoint.